Authorities in the central Chinese province of Henan were holding several ethnic minority Muslim Uyghurs on Friday following a riot triggered by the lifting of a girl's veil, an exile group said.

Meanwhile, officials and residents said the town was "back to normal."

"According to our understanding, the Uyghur detainees have been beaten, and they haven't yet been released," said Dilxat Raxit, spokesman for the Munich-based World Uyghur Congress.

He said 6 or 7 Uyghurs had been detained.

"The injured are still receiving medical treatment," he said.

Around 50 people were injured in Thursday's clashes between riot police and some 1,000 angry Uyghurs who had protested at the Zhenping county offices after a Han Chinese man reportedly lifted the veil of a Muslim Uyghur girl.

Shops, businesses and even banks quickly shuttered their doors when the county's Uyghur residents marched through the streets of Zhenping town, an eyewitness said on Friday.

"There were several hundred Uyghurs ... and lots of business owners and even a bank hurried to shut up shop," he said.

"Not long after that, a lot of armed police showed up, sent from Nanyang," he said, referring to a town around 30 kilometers (19 miles) from Zhenping.

"The armed police came in buses, and sealed off the area around the county government, before surrounding the Uyghurs in a pincer movement," he said.

"They brought in some buses and took the Uyghurs back to Shifosi township."

'Working normally'

An employee who answered the phone at the Zhenping county government offices said, "We are working normally today," but declined to comment further.

Raxit said clashes escalated to involve different groups of residents after some Han Chinese bystanders taunted some of the Uyghurs who were marching to the government buildings.

"The armed police didn't intervene directly to sort this out," he said. "On the contrary, they detained the Uyghurs and beat them up."

Zhenping is known as a jade-carving town and many of the 3,000 Uyghurs living in the county are linked to Hotan, a city famous for high-quality nephrite jade in Xinjiang in northwest of China where the Turkic-speaking Muslim Uyghurs form a majority.

Uyghurs in Xinjiang often complain of policies favoring Han Chinese migration into the region and what they call the unfair allocation of resources to Chinese residents.

In 2009, attacks on Uyghur workers by their Han Chinese colleagues at a toy factory in the southern Chinese city of Shaoguan in Guangdong province triggered protests in the Xinjiang capital Urumqi that sparked China's worst ethnic violence in decades.

Reported by Qiao Long for RFA's Mandarin Service and by Wen Yuqing for the Cantonese Service. Translated and written in English by Luisetta Mudie.